Role of Van Hove singularities and momentum-space structure in high-temperature superconductivity

Journal Article · Wed Dec 01 00:00:00 EST 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.15957· OSTI ID:5630299

Radtke, R J; Levin, K ^[1]; Schuettler, H ^[2]; Norman, M R ^[3]

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1. Department of Physics and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
2. Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602 (United States)
3. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

There is a great deal of interest in attributing the high critical temperatures of the cuprates to either the proximity of the Fermi level to a Van Hove singularity or to structure of the superconducting pairing potential in momentum space far from the Fermi surface; the latter is particularly important for spin-fluctuation-mediated pairing mechanisms. We examine these ideas by calculating the critical temperature [ital T][sub [ital c]] for model Einstein-phonon- and spin-fluctuation-mediated superconductors within both the standard, Fermi-surface-restricted Eliashberg theory and the exact Eliashberg theory, which accounts for the full momentum structure of the pairing potential and the energy dependence of the density of states. Our computations employ band structures chosen to model both the La[sub 2]Sr[sub 2[minus][ital x]]CuO[sub 4] and YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] families. For our spin fluctuation calculations, we take the dynamical susceptibility to be the pairing potential and examine two models of this susceptibility in the cuprates. We compare and contrast these models with available magnetic neutron-scattering data, since these data provide the most direct constraints on the susceptibility. We conclude that a model constrained by neutron-scattering measurements will not yield the observed 90-K [ital T][sub [ital c]]'s regardless of the strength of the electron-spin fluctuation coupling, even when the Van Hove singularity and momentum-space structure are accounted for; moreover, when transport constraints are applied to this type of model, we expect [ital T][sub [ital c]][approx]10 K, as was found in an earlier paper. We also find that the Van Hove singularity enhances [ital T][sub [ital c]] much less effectively than weak-coupling calculations would suggest.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5630299
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 48:21; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HIGH-TC SUPERCONDUCTORS
TRANSITION TEMPERATURE
ELECTRONIC STRUCTURE
FERMI LEVEL
GORKOV-ELIASHBERG THEORY
INELASTIC SCATTERING
NEUTRON BEAMS
PAIRING INTERACTIONS
PHONONS
SINGULARITY
BEAMS
ENERGY LEVELS
INTERACTIONS
NUCLEON BEAMS
PARTICLE BEAMS
PHYSICAL PROPERTIES
QUASI PARTICLES
SCATTERING
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
665411* - Basic Superconductivity Studies- (1992-)